Heat dissipation device having passive fan

ABSTRACT

The present invention relates to a heat dissipation device including a power fan for driving air to flow. The driven air flow drives the impeller of the passive fan to rotate on a support shaft of the heat dissipation seat, thereby generating a sideward wind supply. Therefore, the passive fan may be rotated without needing a power supply, and the passive itself will not generate high temperature and high heat, thereby further increasing the cooling and heat dissipating efficiency thereof on a heat emitting member.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a heat dissipation device having a passive fan, and more particularly to a heat dissipation device for increasing the cooling and heat dissipating efficiency thereof on a heat emitting member.

[0003] 2. Description of the Related Prior Art

[0004] A first conventional heat dissipation device in accordance with the prior art shown in FIG. 1 comprises a heat dissipation plate 92 rested on a heat emitting member 91, and a heat dissipation fan 93 mounted on the heat dissipation plate 92 which is provided with a plurality of heat dissipation fins 94 for increasing the heat dissipation area. The heat produced by the heat emitting member 91 is transmitted to the heat dissipation fins 94 of the heat dissipation plate 92, while the heat dissipation fan 93 is operated to drive the air to in turn flow between the heat dissipation fins 94, thereby achieving the heat dissipation effect for the heat emitting member 91.

[0005] However, the heat dissipation fan 93 has to be energized to operate, so that the heat dissipation fan 93 is also a heat emitting source which produces high temperature and heat, thereby greatly decreasing the cooling and heat dissipating effect.

[0006] A second conventional heat dissipation device (the applicant's own U.S. Pat. No. 6,148,907) in accordance with the prior art shown in FIG. 2 comprises a fan 81 for drawing the ambient cold air outward of a casing 82 into an air inlet pipe 83 to flow into a mantle 84 which is rested on a heat emitting member 85. Therefore, the cold air entering the mantle 84 has a heat exchange function for transferred the heat of the heat emitting member 85 through an air outlet pipe 86 to drain outward.

[0007] However, after the heat of the heat emitting member 85 is transmitted to the mantle 84, only a fan 81, an air inlet pipe 83, and an air outlet pipe 86 are used for transmission, thereby decreasing the heat dissipating effect.

SUMMARY OF THE INVENTION

[0008] The primary objective of the present invention is to provide a heat dissipation device having a passive fan, for providing better cooling and heat dissipating efficiency to a heat emitting member.

[0009] In accordance with the present invention, there is provided a heat dissipation device including a power fan for driving air to flow. The driven air flow drives the impeller of the passive fan to rotate on a support shaft of the heat dissipation seat, thereby generating a sideward wind supply. Therefore, the passive fan may be rotated without needing a power supply, and the passive itself will not generate high temperature and high heat, thereby further increasing the cooling and heat dissipating efficiency thereof on a heat emitting member.

[0010] Accordingly, the heat dissipation device having a passive fan in accordance with the present invention, includes a heat dissipation seat whose surface is provided with a plurality of heat dissipation pieces. Especially, the heat dissipation seat is extended with a support shaft on which a passive fan is rotatably mounted and is supported to rotate, and the passive fan is driven to rotate by an air flow supplied by a power source, thereby generating a sideward wind supply.

[0011] Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a side plan schematic view of a first conventional heat dissipation device in accordance with the prior art;

[0013]FIG. 2 is a side plan schematic view of a second conventional heat dissipation device in accordance with the prior art;

[0014]FIG. 3 is a side plan schematic view of a heat dissipation device having a passive fan in accordance with a first embodiment of the present invention;

[0015]FIG. 4 is an exploded perspective view of a passive fan of a heat dissipation device having a passive fan in accordance with a first embodiment of the present invention;

[0016]FIG. 5 is an exploded perspective view of a heat dissipation device having a passive fan in accordance with a second embodiment of the present invention;

[0017]FIG. 6 is a front plan cross-sectional assembly view of the heat dissipation device having a passive fan as shown in FIG. 5;

[0018]FIG. 7 is an exploded perspective view of a heat dissipation device having a passive fan in accordance with a third embodiment of the present invention;

[0019]FIG. 8 is a front plan cross-sectional assembly view of the heat dissipation device having a passive fan as shown in FIG. 7;

[0020]FIG. 9 is an exploded perspective view of a heat dissipation device having a passive fan in accordance with a fourth embodiment of the present invention;

[0021]FIG. 10 is a front plan cross-sectional assembly view of the heat dissipation device having a passive fan as shown in FIG. 9;

[0022]FIG. 11 is an exploded perspective view of a heat dissipation device having a passive fan in accordance with a fifth embodiment of the present invention; and

[0023]FIG. 12 is a front plan cross-sectional assembly view of the heat dissipation device having a passive fan as shown in FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Referring to the drawings and initially to FIG. 3, a heat dissipation device having a passive fan in accordance with a first embodiment of the present invention mainly comprises a power fan 1, and a passive fan 2, the air flow driven by the power fan 1 is transmitted by a connecting pipe 11 to the passive fan 2 which is combined with a heat emitting member 3.

[0025] The a power fan 1 may be a conventional power fan for driving air to flow. The driven air flow is provided for allowing rotation of the impeller 22 of the passive fan 2. In the preferred embodiment, the driven air flow may be transmitted by the connecting pipe 11.

[0026] Referring to FIG. 4, the passive fan 2 includes a heat dissipation seat 21, and an impeller 22.

[0027] The heat dissipation seat 21 is a flat plate having a surface provided with a plurality of heat dissipation pieces 23. The heat dissipation seat 21 may be formed with a shape such as a circular, square or rectangular shape, and the heat dissipation pieces 23 may be arranged in a radiating manner, or an annular manner, or an inclined manner, or a flow guiding arc-shaped manner. In the preferred embodiment, the heat dissipation pieces 23 are preferably arranged in a radiating manner, and have a middle position defining a receiving space 24 provided with a support shaft 25 on which the impeller 22 is rotatably mounted and is supported to rotate. Accordingly, the entire passive fan 2 may form a smaller thickness. In addition, the receiving space 24 may be provided with a plurality of heat dissipation posts 26 therein without hindering rotation of the impeller 22. Thus, the heat dissipation posts 26 can be used to increase the heat dissipation area of the heat dissipation seat 21.

[0028] The impeller 22 is driven to rotate by the air flow driven by the power fan 1, and has a central position rotatably mounted on the support shaft 25 of the heat dissipation seat 21 to rotate in the receiving space 24 of the heat dissipation seat 21. In the preferred embodiment, the impeller 22 of the passive fan 2 has a central position including a central hub 27 which is provided with a plurality of blades 28 arranged in a radiating manner. The blades 28 of the passive fan 2 may be axial typed blades, or flat plate shaped blades, or centrifugal typed blades. As shown in the figure, the blades 28 have a distal end provided with auxiliary blades 29 extending downward.

[0029] Still referring to FIGS. 3 and 4, when the power fan 1 of the embodiment starts operating, the ambient cold air is introduced into the connecting pipe 11, and blows to the blades 28 of the impeller 22, so that the impeller 22 is rotated on the support shaft 25, and the blades 28 blows the wind toward the flat plate of the heat dissipation seat 21, to generate a sideward wind draining action toward the side faces of the heat dissipation seat 21 for draining the wind to the environment. Thus, the heat produced by the heat emitting member 3 combined on the bottom of the heat dissipation seat 21 of the passive fan 2 is carried away through the heat dissipation seat 21 and the heat dissipation pieces 23, and is carried by the air flow generated by rotation of the impeller 22, while the auxiliary blades 29 creates a sideward wind draining effect to drain the wind to the environment, thereby achieving the cooling and heat dissipation effect. The power required for rotation of the passive fan 2 is derived from the power fan 1 located outside of the passive fan 2 so that during rotation of the passive fan 2, the passive fan 2 itself will not produce any heated gas, so that the cooling air flow driven by the passive fan 2 during rotation will achieve the optimal heat dissipation effect for the heat emitting member 3 combined on the bottom of the heat dissipation seat 21.

[0030] Referring to FIG. 5, a heat dissipation device having a passive fan in accordance with a second embodiment of the present invention comprises a power fan 4, and a passive fan 2 the same as that in the first embodiment.

[0031] The power fan 4 includes a base 41, stator coils 42 provided on the base 41, and an impeller 43 rotatably mounted on a rotation shaft 44 provided on the base 41. The base 41 is combined on the top of the heat dissipation seat 21 of the passive fan 2, and includes a rotation shaft 44, a wind inlet opening 45, and a wind outlet opening 46. The impeller 43 of the power fan 4 is connected with a magnet ring 47 induced with the stator coils 42. The magnet ring 47 may be connected to the outer periphery of the impeller 43, and the stator coils 42 are distributed on the base 41 and located on the outer periphery of the impeller 43.

[0032] Referring to FIGS. 5 and 6, when the power fan 4 of the embodiment is operated, the stator coils 42 on the base 41 are initially energized, so as to induce with the magnet ring 47 of the impeller 43, so that the impeller 43 is driven to rotate. Meanwhile, the ambient cold air is introduced through the wind inlet opening 45 of the base 41, then drained outward through the wind outlet opening 46 of the bottom of the base 41, and enters the inside of the heat dissipation seat 21 through the top of the passive fan 2, so that the impeller 22 inside of the heat dissipation seat 21 is rotated on the support shaft 25, to generate a sideward wind draining action for draining the wind to the environment. Thus, the heat produced by the heat emitting member (not shown) combined on the bottom of the heat dissipation seat 21 of the passive fan 2 is carried away through the side faces of the heat dissipation seat 21, thereby achieving the cooling and heat dissipation effect. Thus, the power required for rotation of the passive fan 2 is derived from the power fan 4 located outside of the heat dissipation seat 21. Therefore, during rotation of the passive fan 2, the passive fan 2 itself will not produce any heated gas, so that the cooling air flow driven by the passive fan 2 during rotation will achieve the optimal heat dissipation effect for the heat emitting member combined on the bottom of the heat dissipation seat 21, thereby increasing the cooling and heat dissipating efficiency of the heat emitting member.

[0033] Referring to FIGS. 7 and 8, a heat dissipation device having a passive fan in accordance with a third embodiment of the present invention comprises a power fan 4, and a passive fan 7.

[0034] The power fan 4 includes a base 41 having a rotation shaft 44 for supporting the impeller 43 to rotate. The base 41 has stator coils 42 induced with the magnet ring 47 of the impeller 43, so that the impeller 43 can be rotated on the rotation shaft 44. The base 41 includes a wind inlet opening 45, and a wind outlet opening 46. The impeller 43 includes blades having a distal end provided with auxiliary blades 48 extended downward into the heat dissipation seat 71 of the passive fan 7.

[0035] The passive fan 7 includes a heat dissipation seat 71, and an impeller 72. The heat dissipation seat 71 has a surface provided with a plurality of heat dissipation pieces 73 having a middle position defining a receiving space 74 provided with a support shaft 75 on which the impeller 43 is rotatably mounted and is supported to rotate. Accordingly, the entire passive fan 7 may form a smaller thickness.

[0036] The impeller 72 is driven to rotate by the air flow driven by the power fan 4, and has a central position rotatably mounted on the support shaft 75 of the heat dissipation seat 71 to rotate in the receiving space 74 of the heat dissipation seat 71. The blades of the impeller 72 may be axial typed blades, or flat plate shaped blades, or centrifugal typed blades.

[0037] Referring to FIG. 8, when the power fan 4 of the embodiment is operated; the stator coils 42 on the base 41 are initially energized, so as to induce with the magnet ring 47 of the impeller 43, so that the impeller 43 is driven to rotate. Meanwhile, the ambient cold air is introduced through the wind inlet opening 45 of the base 41, then drained outward through the wind outlet opening 46 of the bottom of the base 41, and enters the inside of the heat dissipation seat 71 through the top of the passive fan 7, so that the impeller 72 inside of the heat dissipation seat 71 is rotated on the support shaft 75, to generate a sideward wind draining action for draining the wind to the environment. Thus, the heat produced by the heat emitting member (not shown) combined on the bottom of the heat dissipation seat 71 is carried away through the side faces of the heat dissipation seat 71, thereby achieving the cooling and heat dissipation effect. Thus, the power required for rotation of the passive fan 7 is derived from the power fan 4 located outside of the heat dissipation seat 71. Therefore, during rotation of the passive fan 7, the passive fan 7 itself will not produce any heated gas, so that the cooling air flow driven by the passive fan 7 during rotation will achieve the optimal heat dissipation effect for the heat emitting member combined on the bottom of the heat dissipation seat 71, thereby increasing the cooling and heat dissipating efficiency of the heat emitting member.

[0038] Referring to FIGS. 9 and 10, a heat dissipation device having a passive fan in accordance with a fourth embodiment of the present invention mainly comprises a power fan 4, and a passive fan 5.

[0039] The power fan 4 includes a base 41 having a rotation shaft 44 for supporting the impeller 43 to rotate. The base 41 has stator coils 42 induced with the magnet ring 47 of the impeller 43, so that the impeller 43 can be rotated on the rotation shaft 44. The base 41 includes a wind inlet opening 45, and a wind outlet opening 46.

[0040] The passive fan 5 includes a heat dissipation seat 51 having a flat plate provided with a support shaft 55 for supporting the impeller 52 to rotate, and the support shaft 55 is located at a non-central position of the heat dissipation seat 51. The blades of the impeller 52 may be flat plate shaped blades, multi-wing shaped blades, axial flow typed blades, or centrifugal typed blades. The plate of the heat dissipation seat 51 is provided with a plurality of heat dissipation pieces 53 which may be arranged in a flow guiding arc-shaped manner. The support shaft 55 for supporting the impeller 52 is deviated on the heat dissipation seat 51, whereby the impeller 52 is eccentrically operated on the heat dissipation seat 51, so that the flow field (namely, gas channel) inside of the heat dissipation seat 51 possesses a whirl pressurizing effect, thereby increasing the sideward wind draining amount of the passive fan 5.

[0041] Referring to FIG. 10, when the power fan 4 combined with the passive fan 5 of the embodiment is operated, the stator coils 42 on the base 41 are initially energized, so as to induce with the magnet ring 47 of the impeller 43, so that the impeller 43 is driven to rotate. Meanwhile, the ambient cold air is introduced through the wind inlet opening 45 of the base 41, then drained outward through the wind outlet opening 46 of the bottom of the base 41, and enters the inside of the heat dissipation seat 51 through the top of the passive fan 5, so that the impeller 52 inside of the heat dissipation seat 51 is rotated on the support shaft 55, to generate a sideward wind draining action for draining the wind to the environment. Thus, the heat produced by the heat emitting member (not shown) combined on the bottom of the heat dissipation seat 51 is carried away through the side faces of the heat dissipation seat 51, thereby achieving the cooling and heat dissipation effect. Thus, the power required for rotation of the passive fan 5 is derived from the power fan 4 located outside of the heat dissipation seat 51. Therefore, during rotation of the passive fan 5, the passive fan 5 itself will not produce any heated gas, while the support shaft 55 for supporting the impeller 52 is deviated on the heat dissipation seat 51, whereby the impeller 52 is eccentrically operated on the heat dissipation seat 51, so that the flow field (namely, gas channel) inside of the heat dissipation seat 51 possesses a whirl pressurizing effect, thereby increasing the sideward wind draining amount of the passive fan 5. Accordingly, the heat emitting member combined on the bottom of the heat dissipation seat 51 has the optimal heat dissipation effect, thereby greatly increasing the cooling and heat dissipating efficiency of the heat emitting member.

[0042] Referring to FIGS. 11 and 12, a heat dissipation device having a passive fan in accordance with a fifth embodiment of the present invention mainly comprises a power fan 6 combined with a passive fan 2.

[0043] The passive fan 2 includes a heat dissipation seat 21, an impeller 22, heat dissipation pieces 23, a receiving space 24, a support shaft 25, and heat dissipation posts 26.

[0044] The power fan 6 may be a conventional heat dissipation fan, and includes a base 61 provided with a rotatable impeller 62 which has a hub 63 provided with stator coils and a magnet ring (not shown) therein, so that the impeller 62 may be driven to rotate after being energized, to drive an air flow by blades 64, to introduce the air into a wind inlet opening 65 of the base 61 and output the air through a wind outlet opening 66 on the bottom of the base 61, to blow the impeller 22 of the passive fan 2. The blades 64 of the preferred embodiment may be flat plate shaped blades, multi-wing shaped blades, axial flow typed blades, or centrifugal typed blades. Therefore, when the impeller 62 of the power fan 6 is rotated, the impeller 22 on the heat dissipation seat 21 is driven to rotate, thereby generating a sideward wind supply so as to increase the sideward wind draining amount, and thereby increasing the cooling and heat dissipating efficiency of the heat emitting member.

[0045] In comparison with the conventional heat dissipation device, the present invention mainly includes a passive fan having a heat dissipation seat provided with a support shaft for supporting an impeller to rotate, and the passive fan is driven to rotate by the air flow output by the power fan located outside of the heat dissipation seat, thereby generating a sideward wind drain effect toward the side faces of the heat dissipation seat, so that the passive fan can be rotated without having a power source itself, and the passive fan itself will not generate high temperature and high heat, thereby further increasing the cooling and heat dissipating efficiency thereof on a heat emitting member.

[0046] Although the invention has been explained in relation to its preferred embodiment as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention. It is, therefore, contemplated that the appended claim(s) will cover such modifications and variations that fall within the true scope of the invention. 

What is claimed is:
 1. A heat dissipation device having a passive fan, comprising: a power fan (1), for driving air to flow; and a passive fan (2), including a heat dissipation seat (21) provided with a support shaft (25) for supporting an impeller (22) to rotate, the impeller (22) being driven to rotate by an air flow supplied by the power fan (1), thereby generating a sideward wind supply.
 2. The heat dissipation device having a passive fan as claimed in claim 1, wherein the power fan (1) is provided with a connecting pipe (11) for guiding air to an air inlet port of the passive fan (2).
 3. The heat dissipation device having a passive fan as claimed in claim 1, wherein the heat dissipation seat (21) of the passive fan (2) is provided with heat dissipation pieces (23) whose surrounding region defines a receiving space (24) provided with the support shaft (25) for allowing rotation of the impeller (22).
 4. The heat dissipation device having a passive fan as claimed in claim 3, wherein the heat dissipation pieces (23) of the heat dissipation seat (21) are arranged in a radiating manner, or an annular manner, or an inclined manner, or a flow guiding arc-shaped manner.
 5. The heat dissipation device having a passive fan as claimed in claim 1, wherein the receiving space (24) is provided with heat dissipation posts (26) therein without hindering rotation of the impeller (22).
 6. The heat dissipation device having a passive fan as claimed in claim 1, wherein the passive fan (2) includes flat plate shaped blades, or multi-wing shaped blades, or centrifugal typed blades.
 7. The heat dissipation device having a passive fan as claimed in claim 1, wherein the support shaft (55) is provided in the receiving space (54) at a non-central position thereof.
 8. The heat dissipation device having a passive fan as claimed in claim 1, wherein the impeller (22) of the passive fan (2) includes a central hub (27) provided with a plurality of blades (28), and the blades (28) having a distal end provided with auxiliary blades (29) extending downward.
 9. A heat dissipation device having a passive fan, comprising: a power fan (4), including a base (41) provided with a rotation shaft (44) and stator coils (42), the stator coils (42) being energized to drive an impeller (43) to rotate on the rotation shaft (44), to introduce the air into a wind inlet opening (45) and output the air through a wind outlet opening (46); and a passive fan (7), including a heat dissipation seat (71) combined with the power fan (4), the heat dissipation seat (71) provided with a support shaft (75) for supporting an impeller (72) to rotate, the impeller (72) driven to rotate by an air flow supplied by the power fan (4), thereby generating a sideward wind supply.
 10. The heat dissipation device having a passive fan as claimed in claim 9, wherein the base (41) of the power fan (4) includes a plurality of stator coils (42), and the impeller (43) of the power fan (4) is provided with a magnet ring (47).
 11. The heat dissipation device having a passive fan as claimed in claim 9, wherein the impeller (43) of the power fan (4) includes blades having an outer periphery connected with an auxiliary blade (48) for producing a sideward wind supply, the auxiliary blade (48) extending into an inside of the heat dissipation seat (71).
 12. The heat dissipation device having a passive fan as claimed in claim 11, wherein the auxiliary blade (48) is a multi-wing shaped blade, or a flat plate shaped blade, or a centrifugal typed blade.
 13. A heat dissipation device having a passive fan, comprising: a power fan (6), having a center provided with a hub (63) which includes stator coils and a magnet ring therein, so that an impeller (62) may be rotated to drive an air flow by blades (64), to introduce the air into a wind inlet opening (65) and output the air through a wind outlet opening (66); and a passive fan (2), including a heat dissipation seat (21) combined with the power fan (6), the heat dissipation seat (21) provided with a support shaft (25) for supporting an impeller (22) to rotate, the impeller (22) driven to rotate by an air flow supplied by the power fan (6), thereby generating a sideward wind supply.
 14. The heat dissipation device having a passive fan as claimed in claim 13, wherein the impeller (22) of the passive fan (2) includes a central hub (27) provided with a plurality of blades (28), and the blades (28) having a distal end provided with auxiliary blades (29) extending downward. 